Apparatus for telephone-switchboards



N M d 1.) .e o. E. SCRIBNBME P. R. MOBBRTY. APPARATUS FOB. TELEPHONESWITGHBOARDS.

No. 572,223. w Patented Deo. 1', 1896.-

@aviles E 23,07%' 522er @m76 R. 7769/367??y UNITED STATES PATENT OEEICE.

CHARLES E. SCRIBNER, OF CHICAGO, AND FRANK R. MCBERTY, OF

DOYVNERS GROVE, ILLINOIS, ASSIGNORS TO THE VESTERN ELEC- TRIC COMPANY,OF CHICAGO, ILLINOIS.

APPARATUS FOR TELEPHONE-SWITCHBOARDS.

SPECIFICATION forming part of Ietters Patent No. 572,223, dated December1, 1896.

Application filed June 6, b894- Serial No. 513,719. (No model.)

To all whom vit may concern:

Beit known that we, CHARLES E. SCRIBNER, residing at Chicago, in thecounty of Cook, and FRANK R. MGBERTY, residing atDowners Grove, in thecounty of Du Page, State of Illinois, citizens of theUnited States, haveinvented a certain new and useful Improvement in Apparatus forTelephone-Switchboards, (Case No. 356,) of which the following is afull, clear, concise, and exact description, reference being had to theaccompanying drawings, forming a part of this specification.

Our invention relates to the keyboard apparatus oftelephone-switchboards, more particularly to the switching apparatus forconnecting the operators telephone and the generator of signaling-current with the plug-circuit in the operation of establishingcommunication between two telephone-lines comprised within the exchange.

In switchboards commonly in use each telephone-line terminates in asocket upon the switchboard, and the attendant operator at theswitchboard is provided with a number of pairs of connecting-plugsadapted to lit the sockets, the members of each pair being electricallyunited. In combination with the conductors uniting the two plugs of apair several switch-keys are arranged, usually one for switching theoperators telephonie appliances into and out of connection with theplugs and others for looping either plug into circuit with the generatorof signaling-current for operating the signaling-bells at thesubstations. In establishing connect-ion between two telephone-lines theoperator is required to insert one plug of a pair into a socket of eachof the lines to be connected and to manipulate first her listening-key'both for connecting and disconnecting her telephone from theplugcircuit and afterward the callin g-key for signaling to thesubstation of the line with which the connection has been completed-theanswering-line.

It is the object of our invention to perform these operations ofconnecting and disconnecting the telephone and the generator ofsignaling-current automatically at suitable times in the process ofmaking the desired connection, thus relieving the attendant of themanipulation of all mechanism excepting the connecting-plugs themselves,and at the same time dispensing with switch-keyson the face of theswitchboard. To this end we have provided a local circuit in theexchange, normally open and terminating in a contact-piece upon thespring-jack switch or socket of the telephone-line and in a cooperatingcontactpiece upon the connecting-plug, and a relay of peculiarconstruction included in this local circuit having switch-contactscontrolling the circuits between the connecting-plugs and the telephoneand signaling-generator. The operation of inserting the connecting-pluginto a spring-jack to make or complete a desired connection closes theAlocal circuit, whereby all the necessary switching of other appliancesinto and out of circuit is performed.

The instruments which it is especially desirable to thus automaticallyswitch into connection with the plug are, as beforev mentioned, thetelephone and generator of sigmaling-current, and when our relay isrequired to control the circuits of these appliances only it may consistof a lever connected with one conductor of the plug-circuit normallyresting against an anvil constituting a terminal of the telephone, butbrought, when attracted, against a lever which is connected through asuitable yielding connection With a pole of the calling-generator, theyielding connection being adapted to follow its lever only a shortdistance, separating therefrom and thus breaking the circuit of thecalling- .generator before the relay-lever shall have reached itsextreme forward position. The lever carrying the yielding connection, orthis connection itself, may be considerably retarded, if desired, toprolong the moment of connection between the lever and the generator. Incombination with metallic circuits it is desirable to. duplicate theswitch parts, in order to make the necessary connections simultaneouslywith both conductors of the metallic plug-circuit.

It will be understood that our relay is equally well adapted to performany other desired or usual operation of switching whose accomplishmentis required during the time IOO the operator is handling the connecting-plu gs, and, of course, the details of construction herein describedare uncssential toits operation.

Our invention is especially adapted to use in connection with that typeof telephoneswitchboard in which the annunciators are of theself-restoring or self-resetting form, a local circuit being provided incombination with the spring-jacks adapted to be closed through theresetting-magnet of the annunciator when a connecting-plug is insertedinto a spring-jack of the corresponding line. In this type ofswitchboard the local circuit mentioned commonly terminates in twonormally-separated springs in each spring-jack, which springs areyadapted to register with and be crossed together by an insulated ringupon the connecting-plug springs is grounded through a battery or othersource of electric current and the other spring` through the resettingor restoring magnet of the individual annunciator. In adapting ourinvention to this switchboard we `provide a conductor or cord' strandextending to this insulated ring upon the plug and grounded through `themagnet of our relay, this connection being preferably made with thetest-plug or that member of a pair which is employed in completing theconnection;that is, the one which is designed to be inserted into thespring-jack of the answering subscriber.

Our invention is illustrated in the accompanying drawings.

Figure l of the drawings represents in perspective viewthe relay whichperforms the operation of vswitching the different appliances. Fig. 2 isa diagram of two telephonelines extending from substations to atelephone-exchan ge and terminating at the exchange in annunciators andspring-j acks upona switchboard, the telephone-lines being supplied withlocal annunciator-restoring circuits, and plugs and plug-circuits foruniting the lines equipped with our improved relay and arranged withcertain connections appropriate thereto.

' Referring to Fig. l, it will be observed that our relay comprises, asbefore described in a general way, an electromagnet a., controllinganarmature l), carrying two levers c and c', which normally rest againstadjustable anvils d and cl,but which may be brought against theextremities of-pivoted levers c and e. These levers c c are continued`in flexible extensions ff, which normally rest upon contact-anvils g g.rlhe armature h is carried upon a lever h, pivoted in trunnion-screws 7Lh2. The lever 7L carries a horizontal `arm h3, provided at its extremitywith an adjustable hook attached tota retractile spring h4,

' whose other extremity is iixed to a projection of the frame of theinstrument. The levers or arms c c' are rigidly connected with thisarmature-lever h, but are insulated therefrom by an interposed plate ofhard rubber.

One of these -their contact-stops g and g".

The adjustable contact-anvils or stops d d are insulated from. the frameby bushings of hard rubber.

The levers e c' are likewise in mechanical connection with butelectrically insulated from a block i, pivoted on trunnion-screws t" t2,and also provided with an extension 3, fixed to the free extremity of aretractile spring t4. The block or lever 'L' carries a rigid arm t5, towhich the plunger of a dash-pot i is pivoted, retarding the movement ot'the lever.

In the normal position of this apparatus the armature b is drawn backfrom its magnet by spring 71,4, and the contact-levers c and c' restagainst their stops d and d. The lever vl is also retracted by itsspring t4 into a position in which the yielding extensions f and f restupon their anvils g and g, these being adjusted, however, so that thelevers c and c.

do not touch the extremities of levers c and c'.

Vhen the. magnet a is excited, armature b is attracted, withdrawinglevers yc and c from their resting-stops and closing them against theextremities of levers e and e'. In the further motion of armature b thelevers e and c are carried with it in opposition to spring i4, themotion being-retarded by the dash-pot i6. After the levers c e havepassed through a certain predetermined range of motion the yieldingextremities f and f' are lifted from 'When the inagnet d is againdemagnetized, the levers c and c instantly separate from the levers eand c, which latter slowly follow to their normal position, impeded bythe dash-pot i6.

.Referring now/to the diagram, Fig. 2, we will trace the organizationand `operation of our invention in connection with atelephoneswitchboard.

The substations 7c and k are equipped with the usual apparatus,comprising a telephone Z, a genera-tor Z', a signal-bell l2, and anautomatic switch Z3, adapted to be controlled by the telephone to switchthe telephone and the signaling apparatus alternately into circuit,according as the telephone is removed 'from or replaced upon theswitch-hook. Each substation is connected by line-wires with the usualapparatus at the exchange. Thus from vstation 7c extend line-wires l and2, which are connected at the exchange with a spring m and a thimblein", respectively, of each of two spring-jacks n and n and with theextremities of the main or operating coil of an individual annunciatoro. The springjacks n and n may be assumed to be located upon differentsections p and p of a multiple switchboard, the annunciator 0 being uponthe section p.

In addition to the line-contacts m and m each spring-jack is provid-edwith two local contacts or springs m2 m3, the former being connectedalso with asmall ring mAL at the front of the jack for, testingpurposes. Springs fm2 of the different spring-jacks are connectedtogether by a conductor 3 and are IOS IIO

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grounded through the restoring or resetting magnet q of the annunciator0. The springs m3 are connected together by a conductor 4c and aregrounded through a battery r.

The apparatus of substation Zt" is connected with like mechanism at theexchange by linewires 5 and 6, the spring-jacks being lettered in thedrawings n2 and n3 and the annunciator o. The annunciator 0 is supposedto be located upon the section p of the multiple switchboard, so as tobe under the attendance of a different operator. The conductors 7 and 8of the corresponding local circuit are also arranged in a manner exactlysimilar to those of station lo, the batteries r being identical, ifdesired.

The switching mechanism provided for the attending operator is shown atswitchboard p only, a single pair of plugs and accessory devices beingrepresented for the sake of clearness. The plugss and s' each comprise acentral tipi, adapted to register with the line-spring m, an insulatedring or sleeve t to cross together the springs m2 and m3, and a sleevet2, adapted to make connection with the ring 'In'. The tipst of the twoplugs are connected together by a conductor 9 and the sleeves t2 by aconductor lO. The ring t of plug S is insulated, but that of plug s isconnected by a separate flexible conductor ll to earth through themagnet a. of the relay'. A clearing-out annunciator u is provided in apermanent bridge connection between conductors 9 and lO. The levers cand c of the relay are connected with conductors 9 and l0, respectively,while their resting-stops d and d constitute the terminals of theoperators telephone set v. The resting-contacts g and g of levers c ande constitute the terminals vot" a continuously-operating generator a: ofsignaling-current. The circuit of this generator is carried through therestoring or retaining magnet u of clearing-out annunciator u., in orderthat when the generator is connected in a bridge between conductors 9and l0 the clearing-out annunciator shall not be operated by the currentshunted through its main magnet, it being rendered unresponsive at thatmoment by the current of generator x through its restoring-magnet.

To follow the operation of this system, assume that subscriber atstation 7s desires to communicate with subscriber at station k. Thegenerator Z at station 7s being rotated, current is transmitted over theline and through the main magnet of annunciator o, causing the latter todisplay its indicator. The operator at switchboard cl, observing thissignal, inserts the plug s into the spring-jack n of thecorrespondingline at her switchboard. By this means the conductors l and2 are extended through the tipiL and the sleeve t2 of the plug s to theconductors 9 and 10, thence to the levers c and c', and thence to theoperators telephone r. The operator is thus in position to receive theoral order of subscriber at station k for the desired connection. Theoperation of inserting plug s into spring-jack n has crossed togetherthe springs m2 and m3, completing the local circuit of battery r throughrestoring-magi] et q of annunciator o and thus resetting thisannunciator to its normal position.

Having received the order, the operator tests the line called for in theusual way, to determine whether or not it is already in `use--that is,by applying the tip of plug s' to the test-ring m4 of spring-jack n3-andhaving found the line free she insertsthe plug fullyinto spring-jack n3.Local springs nm of this spring-jack are thus closed together,completing the local circuit through the restoring-magnet of annunciatoro', and at the same time conductor ll, through the medium of ring t", isconnected with battery r and current finds circuit therefrom throughmagnet a. The latter being excited attracts its armature. In the irstmovement of the latter the telephone fu is disconnected from conductors9 and l0, the levers c and c being drawn from their contact-anvils d andCl. An instant later levers c and c/ make contact with levers d and d',and since the yielding extensions of these levers still rest againsttheir stops g and g the generator :r is closed in a bridge connectionbetween conductors 9and 10. A signaling-current is thus transmitted tothe substations, operating the bell Z2 at station 7c', where thetelephone is still upon the switch-hook. The levers c and c' now carrywith them the retarded levers e and c, by which the connection of thelatter with anvils g and g is soon interrupted, after which the levers oand c/ are disconnected from all other circuits.

The operations of disconnecting the telephone and of signaling to thesubstation of the answering subscriber to call his attention to thetelephone are thus performed automatically,without the manipulation ofany switching apparatus by the operator.

\Vhen the subscribers have completed their conversation, either or bothmay give the usual signal for disconnecting by rotating hiscalling-generator Z', the signal being received and indicated by theclearing-out annunciator u. The operator then withdraws the plugs s an ds from the spring-jacks. Circuit through magnet a is thus interruptedand the relay is permitted to return to its normal position, in whichthe telephone o is connected with conductors 9 and l0, in condition forcommunication as soon as plug s is inserted into another spring-jack toanswer a call.

As we have before stated, our invention herein described is of abroadand general character, and we do not desire to limit ourselves to anyspecific form of relay or to any particular appliances which the lattermay switch into or out of circuit; and

lVe therefore claim, broadly, as new and desire to secure by LettersPatentl. The combination with a telephone-line,

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' itwith another line by means of a spring-jack' 1 thereof, a relaycontrolling switch-contacts included in the circuit of the telephone,and a local circuit containing the magnet of the said relay terminatingin registering contactpoints of the said plug and spring jack; wherebythe operators telephone is connected with the line until the plug isinserted in the said spring-jack, and is reconnected With the line whenthe plugis removed from the springj ack, -as described.

2. The combination with a pair of Aplugs adapted for insertion intospring-jacks of telephone -lines, the plugcircuit uniting theplugs,'and:an operators telephone in a bridge of the plug-circuit, ofswitch-contacts included in the bridge containing the telephone, anelectromagnet controlling the switch-com vtacts, and a 4local circuitterminating. in reg- Y istering contacts'upon one ofv the plugs and thespring-jacks, completed when the plug is inserted into a spring-jacksubstantially as described.

3. The combination withv telephone-lines terminating in spring-jacks, ofa connectingplug adapted for insertion into one of the spring-jacks, andthe plug-circuit thereof, a generator of signaling-current, and anelectromagnetic switch adapted When excited to connect the generator ofsignaling-current with the plugcircuit, a local circuit independent ofthe line including the electromagnet of said switch terminating incontactpieces adapted to be closed together in the act of inserting theplug into the sprin g-j ack, substantially as described.

4. The combination with a connecting-plug and an operators telephone, ofan electromagnet connected with a circuit of the plug 'adapted tobe'closed during the insertion of the plug in a spring-jack, andswitching mechw anism actuated by said magnet to interrupt the circuitof the telephone, substantially as described.

5. lIn combination, a conductor forming a part or extension of a line toatelephone-substation, a relay having a lever c connected with saidconductor, normally yresting upon a stop CZ connected with a telephone,adapted to makeconnection with and to carry with it a lever e when it isattracted to its magnet, a contact f'electrically conneetedWith saidlever c and adapted to be separated thereby from its restingstop g,means for retarding Vthe movement of lever e, and a generator ofsignaling-current connected with stop g, substantially as described.

In Witness whereof We hereunto subscribe our names this l'7thfday ofMay, A. D. 189i.

'CHARLES E. SCRIBNER. FRANK R.1MCBERTY.

lVitnesses:

GEORGE L. CRAGG, W. GLYDE JoNns.

